| Author |
Message |
Jim Rink (Fakeguy)
Registered Member
Username: Fakeguy
Post Number: 62
Registered: 1-2005
Posted From: 24.33.84.95
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 23, 2007 - 7:08 pm: | |
We and our 62 4106 just returned from a campground where new 50 am service was recently installed. I had a "dog bone" what came with the bus that allowed me to plug in to the 50 amp post and my 30 amp cord into the other end. the result was favorable but have a few questions. I have 3 10,000 Btu AC UNITS on board. Since the voltmeter on my panel was showing 120, I ran 2 at a once showing an AMP draw of 25 total including other 120 draws such as refridge, tv, lamps etc. The breakers on one ac circuit is 15 amp and the other is 20 amp.
Now for my question...is this safe...plugging into 50 amp service with a bus set up for 30 amp and what else should I know and be aware of? All comments appreciated |
Paul Lawry (Dreamscape)
Registered Member
Username: Dreamscape
Post Number: 134
Registered: 5-2007
Posted From: 166.128.223.176
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 23, 2007 - 7:28 pm: | |
What size breakers are in your main electrical panel? If you have a 50amp main breaker then you need to get a 50 amp cord. If you have a 30 amp breaker you will only be able to use that amount of incoming service. I am surprised that with your three roof airs your bus would be set up with a 30 amp breaker. |
Jerry Liebler (Jerry_liebler)
Registered Member
Username: Jerry_liebler
Post Number: 281
Registered: 3-2005
Posted From: 67.141.38.149
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 23, 2007 - 7:38 pm: | |
Jim,
It should be safe IF the bus is wired properly. That means that there is a 30 amp main breaker and other smaller breakers 'below' it. If you only have the 2 breakers you should consider re wireing, as it's possible to draw 35 amps which will overheat a minimal 30 amp cord. You probably should rewire anyway because each air conditioner should be on it's own breaker.
Regards
Jerry 4107 1120 |
James Stacy (Jimstacy)
Registered Member
Username: Jimstacy
Post Number: 106
Registered: 1-2001
Posted From: 75.40.238.238
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 23, 2007 - 8:10 pm: | |
When you plug into a "50 Amp" service (which allows 50 amps draw on each of two legs) and use a 30 amp adapter (30 amp on one leg) it will draw only from one leg, but will allow 50 amp flow.
This means you have a 50 amp breaker on a 30 amp wire. This 50 amp breaker will allow way more current on your 30 amp adapter than the mfg intended. It is important your service cord get to a 30 amp breaker asap for the protection at least after the 30 amp breaker. The adapter will still only have 50 amp protection. Unless your coach was wired to code, you might be able to "cheat" and draw more than the capacity of your power cord. It's not unusual to see a 50 to 30 adapter in meltdown. Be really careful with your loading. As Paul and Jerry were getting to very politely, if you have 3 ac units you should have 50 amp service ability. IMHO
Jim Stacy |
Jim Rink (Fakeguy)
Registered Member
Username: Fakeguy
Post Number: 63
Registered: 1-2005
Posted From: 24.33.84.95
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 23, 2007 - 9:08 pm: | |
Wow..thanks for all the great and quick combacks. I need to clarify a few things on my original post.
1. Paul..not sure what what my main breaker is...will check but guessing 30 amp.
2. I have a separate circuit (1 20 amp and 2 15AMP) for each ac unit which are not roof type. They are Frigid King built in: 2 below deck and 1 built into the rear cabin.
Will check main next weekend and report back...meanwhile thanks again and any more comments welcomed |
Gus Causbie (Gusc)
Registered Member
Username: Gusc
Post Number: 503
Registered: 11-2005
Posted From: 63.97.117.39
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 26, 2007 - 5:23 pm: | |
Jim,
Now I'm confused. On one of the boards I read that a 50a-30a adapter uses just one 25a leg of the 50a outlet?? |
Richard Bowyer (Drivingmisslazy)
Registered Member
Username: Drivingmisslazy
Post Number: 1992
Registered: 1-2001
Posted From: 75.108.72.199
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 26, 2007 - 6:41 pm: | |
Gus, there is no 25 amp leg on a 50 amp outlet.
There are two hot legs, each rated at 50 amps each. Voltage between the two hot legs is 240 volts. Voltage between either hot leg and neutral is 120 volts.
Richard |
John MC9 (John_mc9)
Registered Member
Username: John_mc9
Post Number: 518
Registered: 7-2006
Posted From: 66.217.101.111
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 26, 2007 - 9:28 pm: | |
Richard -
We've been to many, many campgrounds, where the "50 amp"
receptacle consisted of a 30a leg and a 20a leg. The circuit breaker
panel usually had one 30 and one 20 installed for that receptacle..
(several campgrounds used the older glass screw-in fuses)
Yeah, it's not right... and yeah, it should be 50a per leg x2 in the
"official" 220v capacity.... But.... The campgrounds only tell you
they provide "50 amp service", -not- 220v service, and finding that
there is only a total of 50 amps service from a provided outlet
should never be a surprise to anyone.
Everyone should be made aware of the lack of conformity, and
the disregard of codes at campgrounds. Safety of service should
never be taken for granted.
"I don't think we're in Kansas anymore, Toto" |
Paul Lawry (Dreamscape)
Registered Member
Username: Dreamscape
Post Number: 138
Registered: 5-2007
Posted From: 64.40.222.139
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 26, 2007 - 11:08 pm: | |
What Richard said, that is the correct information. |
George M. Todd (George_mc6)
Registered Member
Username: George_mc6
Post Number: 270
Registered: 8-2006
Posted From: 207.231.75.253
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 27, 2007 - 12:48 am: | |
Paul,
John is right too.
Also what MUST be looked at is Sean's post on mis-wired 50 amp campground services! If one of these joints uses the same hot leg to power the 20 and 30 amp receptacles, the neutral current can be right at 50, without tripping any breakers. Two 30 amp receptacles adapted together to run a 50 amp service will melt the neutral if they're not on opposite legs!
So, check for voltage between the hot legs. 240V is correct, 0 is TROUBLE!
Thanks Sean for thinking about this!
George |
John MC9 (John_mc9)
Registered Member
Username: John_mc9
Post Number: 520
Registered: 7-2006
Posted From: 66.217.105.39
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 27, 2007 - 2:21 am: | |
Ditto, George! And Thanks!
What should be found at campgrounds, isn't always found.
It's best to take a voltmeter,or an inexpensive "Kill-A-Watt"
unit, and test every power pole you intend to hook to. Test
the ground bond as well.
Much can be learned at the RV forums; they're not travelling
in million dollar rigs, and staying at high end resorts. The small,
no-frill, romantic hideaways, are where you'll find the variables....
(and, at many county and state campgrounds)
(well worth it, tho!)
Thanks again, George! |
Sean Welsh (Sean)
Registered Member
Username: Sean
Post Number: 672
Registered: 1-2003
Posted From: 67.142.130.31
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 27, 2007 - 12:38 pm: | |
George wrote:
Also what MUST be looked at is Sean's post on mis-wired 50 amp campground services!
The post to which George refers is in another thread. Here's a direct link:
http://www.busnut.com/bbs/messages/11/18971.html?1190606939#POST120026
-Sean
http://OurOdyssey.BlogSpot.com |